1. Field
This invention relates to impact printers and more particularly to an improved print hammer actuating device for an impact printer.
2. Description of the Prior Art
Existing serial impact printers which utilize a single type element such as type ball printers and daisy wheel printers are restricted by problems of inertia and space in the size of characters they can print given a specified character set or alphabet. Such printers presently employ sophisticated electronic controls which can be economically mass-produced. While techniques are known to provide printers of alternate configurations such as typebar typewriters which are capable of printing large characters, it is particularly desirable to employ a configuration that could also make virtually direct use of existing electronic controls, thereby substantially reducing the cost of the printer.
Proposals such as those shown in U.S. Pat. No. 3,892,303 issued July 1, 1975 to Willcox, and U.S. Pat. No. 3,731,778 issued May 8, 1973 to Willcox provide a serial printer configuration where a character selection device variously known as a carousel cartridge, type chip cartridge or supply wheel carries a group of typeface chips, each bearing one character of a character set. Additional mechanism is provided to transfer a chip from the supply wheel to a light-weight impact print hammer and still further mechanism operates the hammer to impact the type against the paper or other writing media. The separation of the type element from the character selection device in these U.S. patents overcomes much of the inertial and spatial limitations which limit character size in more conventional daisy wheel or type ball printers. However, the added complexity of the separate supply wheel and hammer call for a number of operations not present in the more conventional printers and thus the devices as shown in the prior patents are not controllable directly by controls otherwise designed for the more conventional printers.